Search results for "Geometric morphometrics"
showing 10 items of 29 documents
Categorical versus geometric morphometric approaches to characterizing the evolution of morphological disparity in Osteostraci (Vertebrata, stem Gnat…
2020
Morphological variation (disparity) tends to be evaluated through two non-mutually exclusive approaches: (i) quantitatively, through geometric morphometrics, and (ii) in terms of discrete, ‘cladistic’, or categorical characters. Uncertainty over the comparability of these approaches diminishes the potential to obtain nomothetic insights into the evolution of morphological disparity, and the few benchmarking studies conducted so far show contrasting results. Here, we apply both approaches to characterising morphology in the stem-gnathostome vertebrate clade Osteostraci, in order to assess congruence between these alternative methods as well as to explore the evolutionary patterns of the grou…
Morphometric diversity of the mussel Brachidontes pharaonis in different coastal environments
2010
In the debate on how and why biodiversity evolves spatially and temporally and in an attempt to assess the further effects of anthropogenic activities, the ability of marine invertebrate to express a large spectrum of phenotypical plasticity can have a central role. The ability of a single genotype to produce more than one alternative form of morphology and/or physiological state should be larger in species living in highly changing waters like shallow habitats. Invertebrates, there, usually experience ample changes of temperature and food availability on annual, seasonal, diurnal and hourly bases which are the two main drivers leading the life histories of these organisms. In such circumst…
Species identification of the psammophilous tenebrionid beetles Phaleria acuminata Juster, 1852 and Phaleria bimaculata (Linnaeus, 1767) from central…
2013
Dominating global arid environments, from desert to coastal dunes, most Tenebrionidae are highly specific in their habitat preferences and display limited dispersal potential, thus exhibiting a remarkable degree of regional genetic and morphological differentiation. The tenebrionid genus Phaleria is speciose and widely distributed, with P. acuminata and P. bimaculata having a wide Mediterranean distribution, with numerous morphological differentiations at population level, often described as different taxa of doubtful taxonomical significance. In order to investigate the variability of the central Mediterranean populations of P. bimaculata and P. acuminata and to compare the results obtaine…
(no title)
2017
Biological invasions are recognized as a significant evolutionary factor over short time scales. In particular, their effect is well recorded on the genetic structure of populations, the patterns of phenotypic evolution and the richness of parasite fauna associated to invasive populations. This study aims at quantifying the consequences of a biological invasion according to these three levels (genetical, phenotypical and parasitological) taking as example the Mozambique tilapia Oreochromis mossambicus. This African cichlid is characterized by an unusual conservation status since it is both (i) ranked among the world's worst invasive species due to its global dispersion during the 20th centu…
The Human Biodiversity in the Middle of the Mediterranean. Study of native and settlers populations on the Sicilian context
2020
[IT] Negli ultimi 200.000 anni, la specie umana si è diffusa in tutta la Terra, adattando la sua morfologia e fisiologia a un'ampia gamma di habitat. Lo scheletro umano ha quindi registrato i principali effetti ambientali e di conseguenza i reperti scheletrici assumono grande importanza nell'indagine dei processi evolutivi. Oggi le moderne tecniche di indagini quantitative delle principali caratteristiche morfologiche consentono di metterle in relazione con la variabilità genetica. La posizione geografica della Sicilia, l'isolamento e la sua lunga e dinamica storia di colonizzazione (diversi e numerosi contributi culturali e biologici) hanno creato un contesto peculiare che consente uno stu…
Human-induced hybridization and population bottleneck : population genetics, morphometrics and parasitology applied to the invaded and invasive tilap…
2011
Biological invasions are recognized as a significant evolutionary factor over short time scales. In particular, their effect is well recorded on the genetic structure of populations, the patterns of phenotypic evolution and the richness of parasite fauna associated to invasive populations. This study aims at quantifying the consequences of a biological invasion according to these three levels (genetical, phenotypical and parasitological) taking as example the Mozambique tilapia Oreochromis mossambicus. This African cichlid is characterized by an unusual conservation status since it is both (i) ranked among the world’s worst invasive species due to its global dispersion during the 20th centu…
Association between ribs shape and pulmonary function in patients with Osteogenesis Imperfecta
2019
Graphical abstract
The torso integration hypothesis revisited in Homo sapiens: Contributions to the understanding of hominin body shape evolution.
2018
Objectives: Lower thoracic widths and curvatures track upper pelvic widths and iliac blades curvatures in hominins and other primates (torso integration hypothesis). However, recent studies suggest that sexual dimorphism could challenge this assumption in Homo sapiens. We test the torso integration hypothesis in two modern human populations, both considering and excluding the effect of sexual dimorphism. We further assess covariation patterns between different thoracic and pelvic levels, and we explore the allometric effects on torso shape variation. Material and Methods: A sex-balanced sample of 50 anatomically connected torsos (25 Mediterraneans, 25 Sub-Saharan Africans) was segmented fro…
Explorative 3D geometric morphometrics on crania and mandibles of Cercopithecini (1024 specimens)
2015
A dataset of crania and mandibles from Old World primates was investigated through the use of 3D Geometric Morphometrics. We focused the attention on the tribe Cercopithecini, sampling 1024 specimens preserved in 9 different museums and related to a total of 31 species. Other 102 specimens belonging to 10 species of the same family Cercopithecidae were added as outgroup. Our sampling campaign was carried on with a 3D-digitizer Microscribe G2X and the data were processed through the softwares Morphologika and MorphoJ. We conducted both PCA and CVA analyses to investigate the power of resolution of the morphometric method and to understand the role of a-priori groups in the discrimination of …
Functional assessment of morphological homoplasy in stem-gnathostomes
2021
Osteostraci and Galeaspida are stem-gnathostomes, occupying a key phylogenetic position for resolving the nature of the jawless ancestor from which jawed vertebrates evolved more than 400 million years ago. Both groups are characterized by the presence of rigid headshields that share a number of common morphological traits, in some cases hindering the resolution of their interrelationships and the exact nature of their affinities with jawed vertebrates. Here, we explore the morphological and functional diversity of osteostracan and galeaspid headshields using an innovative approach that combines geometric morphometrics and computational fluid dynamics, thereby constraining the underlying fa…